Automatic emergency actuator for power brakes



Aug. 22, 1950 F. A. LETNER 2,519,774

AUTOMATIC EMERGENCY ACTUATOR FOR POWER BRAKES Filed Nov. 20, 1946 3 Sheets-Sheet l Inventor Frank A Lefner Aug. 22, 1950 F. A. LETNER 2,519,774

AUTOMATIC EMERGENCY ACTUATOR FOR POWER BRAKES Filed Nov. 20, 1946 3 Sheets-Sheet 2 IHH Fig. 2.

Frank A. Letner Aug. 22, 1950 F. A. LETNER AUTOMATIC EMERGENCY ACTUATOR FOR POWER BRAKES 3 SheetsSheet 5 Filed Nov. 20, 1946 Fig. 4.

I mz'lltor Frank A. Lerner W a Attorm ys Patented Aug. 22, 1950 AUTOMATIC EMERGENCY ACTUATOR FOR POWER BRAKES Frank A. Letner, Del Paso Heights, Califi, assignor of one-half to William L. Davis, Augusta, Ga.

Application November 20, 1946, Serial No. 711,154

The present invention relates to novel and useful improvements in automatic actuator for power brakes and more specifically pertains to an ap paratus which may be attached to a conventional power brake system of vehicles for the purpose of automatically applying the brake upon the failure of the power brake system of the vehicle.

The principal objects of my invention reside in providing an apparatus which may readily be attached to existing vehicles having a power brake operating system; which is so associated with the conventional power brake operating system that it remains out of operation when the pressure medium of the power brake system is normal or adequate, but is thrown into operation when the pressure of the power brake system falls below a predetermined safe minimum; which makes use of the movement of the vehicle to produce a power actuating means for applyin the brakes of the vehicles; which is provided with novel, efiicient and simple control means for selectively energizing or de-energizing the apparatus.

Other ancillary objects of the invention which will later become apparent as the following description proceeds, are realized by my invention, one embodiment of which has been illustrated in the accompanyin drawings, wherein:

Figure 1 is a diagrammatic top plan view of a portion of a vehicle frame showing the relative position of the various parts of my invention;

Figure 2 isa side elevational view of the operating unit of my invention;

Figure 3 is a longitudinal sectional view through V the fluid pressure cylinder and piston for applying the emergency brakes;

Figure 4 is a detail in elevation showing the power supplyin means for my invention;

Figure 5 is a vertical sectional view being taken substantially upon the line 55 of Figure 2;

Figure 6 is a, detail in vertical section being taken substantially upon the line 65 of Figure 2; and

Figure '7' is a detail view in elevation showing the manner of attaching my invention to the service brakes of a vehicle.

Referring now more specifically to the attached drawings, wherein like numerals designate similar parts throughout the various views, reference is made first to Figure 1 for a general understanding of the invention, and wherein I0 designates a portion of a vehicle frame which is provided with the usual vehicle wheels 12 and a fluid pressure reservoir M which is connected by any suitable means for supplying pressure Claims. (Cl. 188-106) fluid to any conventional type of fluid pressure power brake operatin mechanism, not shown. The reservoir M is provided with a flexible conduit l5 establishing free communication with a control cylinder ['8 for controlling the operation of my safety attachment upon failure of the power brake operating pressure in the reservoir M, A connecting rod 20 operated by my safety device in a manner to be subsequently set forth is suitably connected to a lay shaft 22 which is provided with arms 24 for operating the actuating rods 28 which are connected to the brake operating arms of the vehicle for actuation thereof independently of the power brake operating means in a manner to be subsequently set forth.

As shown best in Figure l, the rear axle housing 28 of the vehicle has adjustably secured thereon a pair of clamps 30 which rotatably support a drive shaft 32 upon whose outer end is mounted a gear 34 constantly in mesh with an internal gear 36 mounted in any suitable manner upon the hub of one of the vehicle wheels l2. The inner end of the shaft 32 is connected by means of a universal joint 38, a connecting shaft 40, universal joint 42, shaft 44, and an extension coupling 46 and shaft 48 with a drive shaft 50. The couplin 46 is provided for the purpose for varying the length of the driving shafts 4G and 48 in order to fit the device to various types and models of vehicles, and the coupling shaft 40 and universal joints 38 and @2 further assist in locating the apparatus in any desired location upon a vehicle. As shown in Figures 2 and 4, constantly meshing gears 52 and 54 drivingly conmeet the shafts 48 and Ell respectively.

Attention is now directed more specifically to Figure 2, wherein a suitable casing or frame work 56 is provided which is adapted for rigid engagement with the frame of a vehicle in any suitable manner and in any desired location. The shaft 48 is journaled in this frame work 56 in any preferred manner, not shown, while the shaft 59 is rotatably mounted therein as by bearings 53 and 60. The shaft 50 is connected by means of a clutch indicated generally at 62' with the crank shaft 64 of a reciprocating piston pumping unit having cylinders 66. The pressure responsive cylinder i8 is mounted upon the frame work 56 and is provided with an axially extending reciprocable operating rod 68 which is reciprocated by any conventional mechanism within the cylinder l 8, not shown, in response to pressure variations within the cylinder is as communicated or introduced by the conduit 16 in a manner to be subsequently set forth. A coil spring 1Q nor-w 3 mally urges the rod 68 outwardly of the cylinder I8 against the action of the pressure fluid introduced by the conduit I6. An operating lever 12 has its upper end connected in any suitable manner to the rod 68, and is fulcrumed as at M to the casing 56. Intermediate its ends, the lever 12 is connected to a clutch control element 16 for operating the clutch 62 and at its outer end is pivotally connected as at I6 to a control line 86 pivoted to a lever 82 for actuation of a valve indicated generally at 84. A fluid tank 86 is secured in any suitable position as upon the casing 56 and is provided with a conventional filling cap 88. A suction line 90 connects the tank 86 with the cylinder 66 of the pumping unit and i provided with non-return check valves 62 preventing reverse flow through the passage 90 from the pump into the tank 86. Preferably formed integrally with the casing member 56, is a horizontally disposed cylinder 94 which is open at both ends as shown in Figure 3. The outer end of the cylinder is provided with a filtering element 96 and a detachable closure cap 98 which is apertured or perforated as at I to freel emit the passage of air therethrough for a purpose to be subsequently set forth. At its other end, the cylinder 94 is provided with a head I02 and which is bored to slidingly receive the rod referred to hereinbefore. A piston I04 is secured upon the end of the rod 20 and is slidably disposed in the cylindrical member 94 while a suitable packing means I06 prevents the escape of pressure fluid through the head I02. A pump pressure or discharge line I08 is connected with the cylinder 94 behind the piston I04 and is in communication with the pump cylinder 66 through the nonreturn check valves III] which permits flow of fluid from the pump to the cylinder but prevent return flow. A fluid return line H2 is in communication by means of the valve member 84 with the pressure chamber between the piston I04 and the cylinder head I62, and is in free communication with the interior of the reservoir 66. The actuating rod 26 extends through the casing 56 between a pair of parallel rolls II-i which rolls are provided with parallel longitudinally disposed guide slots II6. A transverse guide and stop member H8 is rigidly secured to the rod 20 and is disposed for sliding movement in the slot I I6, a return spring I 26 encircling the rod 20 between the stop H2 and one end of the end slotted portion of the casing 56.

.As set forth above, the operating rod 20 is operatively connected with the brake actuating linkage 26 which is provided with headed portions I22. The rods 26 extend through suitable apertures I23 in the outer end of brake operating arms I24 adapted to operate the vehicle brakes in the conventional manner, it being noted as shown in Figure '7, that the brake operating arms I24 are provided with bores I26forengagement by the customary power brake operating mechanism, not shown. As will be understood, the aperture I23 is freely slidable upon the linkage 26 when the lever I24 is operated by the service brake through the eyelet I26 in the usual manner, but when the linkage 26 is actuated, the headed portion I22 is moved to take-up the slack in the system and operate the lever I24.

The operation of my device is as follows. As long as the usual fluid pressure or vacuum of the conventional power brake operating system is at its normal value, and communicated by the conduit I6 to the control cylinder I8, said fluid j pressure opposes the action of spring 10 and urges 4 the control rod 68 inwardly of the cylinder I8 against the action of said spring. When the device is maintained in this condition, the lever 12 through its attachment 16 disengages the clutch 62, whereby the driving shaft 50 is disengaged from the crank shaft 64 of the pump. In this position of operation, the connections 12, 14, 18, B0 and 82 simultaneously retain the valve 84 in a position whereby the interior of the pressure chamber between the piston I04 and head I02 is vented to the fluid storage tank 86, thereby rendering the piston I04, operating rod 20, linkage 26 inoperative to apply the vehicle brakes. It may be here noted that during the entire time the vehicle wheels are in motion, the connecting means 36, 34, 32, 38, 46, 42, 44, 46, 48, 50, 52 and 54 are maintaining the shaft 50 in constant rotation. In other words, the shaft 50 is in continuous and constant engagement with the wheels of the vehicle. When new the operating pressure of the vehicle reservoir I4 falls below the safe operating pressure, this drop in pressure is communicated to the cylinder I8, and now permits the spring I0 to urge the rod 66 outwardly of the cylinder. The spring I0 thereupon urges the rod 66 into a position which rotates the lever I2 about its axis 14, and through the connection 16 engages the clutch 62 whereby the driving shaft 50 is placed in driving engagement with the crank shaft 64 of the pump unit. At the same time, the interconnected linkage causes the closing of the valve member 84 thereby breaking the free connection between the pressure chamber of the cylinder 94 and the fluid reservoir 86. In this condition, any movement of the vehicle wheels I2 causes operation of the pumping unit and draws in fluid from the reservoir 86 by means of the conduit 90 and check valves 92, into the cylinder 66 and discharges the same under pressure through the conduit I08 and valves IIO into the pressure chamber of the cylinder 94. This fluid under pressure urges the piston inwardly of the cylinder, and thereby actuates the rod 20 against the action of the return spring I20 to operate the linkage 26 and apply the service brakes through operation of the brake lever or brake arm I24. I desire at this time to point out that this operation occurs regardless of whether the vehicle is in motion and experiences a sudden failure of the fluid pressure of the power brakes or whether the vehicle during a period of standing should gradually lose the operating pressure of the power brakes. latter event, if the vehicle starts to move, the operation of the pumping unit Will build up pressure in the pressure chamber of the cylinder 84 to apply the brakes; and this pressure is maintained by means of the closing of the valve 84, and the non-return check valves IIO, to set and hold the brakes in their applied position. This brake applying pressure of my safety device can only be released by a restoration of the service brake pressure of the automatic power brake system, when the said pressure has been applied to the control cylinder through the conduit I6, and thereby releases the brake application of my.

safety device in the manner mentioned herein the filtering or cleaning means 96 serves to exclude the presence of dirt, grit or the like from thecylinder 94. v V

In theagsmwms 7 1}. Air auxiliar es actuator sys-teinifor: braking; a Wheeledivehioleemployingaarmaim.pressurerbrake: system, said: auxiliar gactuator system beingirendimedi operative"; upon default; of; thecmain; brake. system; and including: am actuating linkagafor operating the brakes of a vehicle, a flrstmeans for:operating:said.v actuating linkage, a second means responsive to motion of said vehicle for supplying fluid pressme t'o said first means, a thirdtmeanssresponsivertogar predetermined pressure in the power service brakeesystem'iofr said: vehicle for, preventingoperationioi. said second means, said"first m'eansincludin'g a cylinder, a pistoniiirsaid cylinder, a connecting rod'opera secured to said piston and said actuating linkage, aa-springiurging said connectingrod-and said actuating linkage into inoperative position, a guide means for restraining said connecting rod to straight line motion.

2. An auxiliary actuator system for braking a vehicle employing a main pressure power brake system, said auxiliary actuator system being operative upon deactivation of the main brake system and including an actuating linkage for operating the brakes of a vehicle; means for operating said actuating linkage, means responsive to the motion of the vehicle for actuating said operating means, clutch means for said last means and means reactive to a default of the main brake system for actuating said clutch means.

3. An auxiliary actuator system for braking a wheeled vehicle employing a main pressure power brake system, said auxiliary actuator system being operative upon deactivation of the main brake system and including an actuating linkage for operating the brakes of a vehicle, means for operating said actuating linkage, power means associated with the wheels of the vehicle and responsive to the rotation thereof for actuating said operating means, clutch means for said last means and means responsive to a loss of operating pressure in the main brake system for actuating said clutch means.

4. An auxiliary actuator system for braking a wheeled vehicle employing a main pressure power brake system, said auxiliary actuator system being operative upon deactivation of the main brake system and including an actuating linkage for operating the brakes of a vehicle, means for operating said linkage, means responsive to motion of the vehicle for supplying fluid pressure to said operating means, said last means including a fluid pressure pump and power means for said pump associated with and driven by the wheels of the vehicle, clutch means for said power means, and means responsive to a predetermined pressure in the main pressure system of said vehicle for controlling said clutch means.

5. An auxiliary actuator system for braking a Wheeled vehicle employing a main pressure power brake system, said auxiliary actuator system being operative upon deactivation of the main brake system and including an actuating linkage for operating the brakes of a vehicle, pressure actuated means for operating said linkage, means responsive to motion of the vehicle for supplying a fluid pressure to said foregoing means, said last means including a fluid pressure pump and driving means for said pump, said driving means being drivingly associated with the wheels of the vehicle and reactive to the rotation thereof, clutch means connecting said driving means to the pump, means responsive: to a; predetermined pressureeim thermaim power: brake: system; for controlling? the opera? tion of. the clutchvmeans; said; lastsmeans: ins eluding: as pressure: responsive member an'dras membenoperativelyi: connecting, said; pressure; sponsive member. and: said: clutchz. means.

6. An: auxiliairy actuators" system for brakingraa wheeled: vehicle employing amainpressurmpower brake; system; said'lauxiliary; actuator: systemxble'q ing: operative. upon: deactivation ofz-the main brakeisystemrandlincluding:aniactuatingilinkaga for: opera-ting: the. brakes of: arvehicla. pressure operatedzmeans for'actuating. said linkagemeans responsive: to; motion; or: the: vehicle for: supplyw' ing-:,a.fli.1id:;pressure. to; said; foregoing: means,- sai'di lastrneans.,inoludingiaifluid pressure; pump;,driv:- ing; means; for: said; pumpx actuated by -saidivehieole; ax fluid; storage tank, said: pumpcv having: a: suction line communicating with said tank and a pressure line connecting with said pressure operated means, non-return valves in said suction and pressure lines, a return line connecting said pressure operated means to said tank, valve means in said return line, clutch means connecting said driving means to the pump, and means responsive to a loss of operating pressure of the main brake system for controlling the operation of the clutch means.

7. An auxiliary actuator system for braking a Wheeled vehicle employing a main pressure power brake system, said auxiliary actuator system being operative upon deactivation of the main brake system and including an actuating linkage for operating the brakes of a vehicle, pressure operated means for actuating said linkage, means responsive to motion of the vehicle for supplying a fluid pressure to said foregoing means, said last means including a fluid pressure pump, driving means fo said pump actuated by said vehicle, a fluid storage tank, said pump having a suction line communicating with said tank and a pressure line connecting with said pressure operated means, non-return valves in said suction and pressure lines, a return line connecting said pressure operated means to said tank, valve means in said return line, clutch means connecting said driving means to the pump, and means responsive to a loss of operating pressure of the main brake system for controlling the operation of the clutch means.

8. An auxiliary actuator system for braking a wheeled vehicle employing a main pressure power brake system, said auxiliary actuator system being operative upon deactivation of the main brake system and including an actuating linkage for operating the brakes of a vehicle, pressure operated means for operating said linkage, means responsive to motion of the vehicle for supplying pressure to said operating means for the linkage, clutch means for said last means, means responsive to a working pressure in the main power brake system for retaining said clutch means in a disengaged relation and means reactive to deleterious reduction of pressure in the main brake system for engaging said clutch means.

9. An auxiliary actuator unit for braking a vehicle equipped with a main pressure power brake system, said auxiliary actuator unit being inoperative during normal working operations of the main power brake system and including operating means associated with the brakes of a vehicle, pressure operated actuating means for said brake operating means; power meansior said actuating means, said power means semi actuated responsive to and in accordance with motion of the vehicle, clutch means for said power means, means responsive to a normal operating pressure in the main brake system for retaining said clutch means disengaged and means for engaging said clutch means responsive to a default of the main brake system.

1 An auxiliary actuator unit for braking a vehicle equipped with a main pressure power brake system, said auxiliary actuator unit beinginoperative during normal working operations of the main power brake system and including linkage means associated with the brakes of a vehicle, pressure operated actuating means for said linkage means, means for supplying a 5 Number fluid pressure to said foregoing means, said supplying means including a fluid pressure pump, driving means for said pump associated with the REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date 1,903,973 Boughton Apr. 18, 1933 2,142,514 Jones Jan. 3, 1939 FRANK A. LE'INER! 

